Electromagnetic properties and electronic structure of iron-based layered superconductor LaOFeP

TL;DR

This study investigates the structural, electronic, and magnetic properties of LaOFeP, revealing how doping affects superconductivity and elucidating the electronic structure and magnetic behavior through spectroscopy and calculations.

Contribution

It provides new insights into how aliovalent doping influences Tc and clarifies the electronic and magnetic structure of LaOFeP using combined experimental and theoretical methods.

Findings

Tc increases with Ca and F doping.

LaOFeP exhibits paramagnetism in the normal state.

Fe 3d orbitals hybridize with P 3p to form a Fermi surface.

Abstract

Structural, electronic, and magnetic properties of undoped and aliovalent-ion (Ca, F)-doped LaOFeP, which undergo superconducting transitions at transition temperatures (Tc) 4-7 K [Kamihara et al, J. Am. Chem. Soc. 128, 10012, (2006)], were investigated. Tc of the samples varied from 2.4 to 5.5 K in the undoped samples, and was increased up to ~7 K by Ca- and F-doping. The Tc increases are correlated with a decrease in the lattice volume. LaOFeP exhibits paramagnetism in the normal conducting state. Photoemission spectroscopy combined with first-principle band calculations clarified that Fe 3d (dz2 + (dxz, dyz)) orbitals hybridized with P 3p to form a Fermi surface. The band calculations also suggest that the 3d electron of the Fe in LaOFeP is basically in the low-spin configuration, and that the spin moment of LaOFeP is almost quenched, leading to the paramagnetism of the itinerant electrons.